1. Field of the Invention
This invention generally relates to compressed image and video coding and, more particularly, to a method for filtering ringing artifacts that may occur as a result of compressed image and video encoding/decoding processes.
2. Description of the Related Art
Computation resources and bandwidth can be saved by encoding images and videos at a low bit-rate. However, low bit-rate encoding may result in several types of artifacts in the decompressed images. The most notable artifacts include blocking and ringing artifacts. The ringing artifacts are typically observed around the true edges of an image. The ringing artifacts are also referred to as mosquito artifacts, as they tend to be annoying, especially in moving images (video sequences). A variety of filters exist for filtering out these unwanted artifacts. These include de-blocking and de-ringing filters. For de-ringing, conventional methods operate in both the transform and pixel domains. Other conventional de-ringing filters make use of quantization information. One drawback of all the above-mentioned de-ringing filters is that are computationally intensive. Thus, the filters are not suitable for all receiving systems. Further, the filters may result in unacceptable delays, even when they can be implemented.
It would be advantageous if a low complexity de-ringing filter could be developed for ringing artifact reduction.